I have a 1999 GMC with a 454 Vortec in it. It starts everytime, but it is a hard start when it has been run or the temp outside is hot. In the morning it cranks right over. I have a hunch it is a fuel pump problem, but don't know. My oil pressure fluctuates quite a bit too. I know some of you know your GM stuff, so let me know what you think.